A revised interpretation of the Chon Aike magmatic province: Active margin origin and implications for the opening of the Weddell Sea
Late Triassic – Jurassic igneous rocks of the Antarctic Peninsula and Patagonia provide evidence for the evolution of the margin of southwestern Gondwana. We present new geochronological (LA-ICP-MS zircon U\Pb dates) analyses of 12 intrusive and volcanic rocks, which are complemented by geochemical...
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ftunivgeneve:oai:unige.ch:unige:152181 2023-05-15T13:51:22+02:00 A revised interpretation of the Chon Aike magmatic province: Active margin origin and implications for the opening of the Weddell Sea Bastias Silva, Miguel Joaquin Spikings, Richard Alan Riley, Teal Ulianov, Alexey Grunow, Anne Chiaradia, Massimo Hervé, Francisco 2021 https://archive-ouverte.unige.ch/unige:152181 eng eng info:eu-repo/semantics/altIdentifier/doi/10.1016/j.lithos.2021.106013 unige:152181 https://archive-ouverte.unige.ch/unige:152181 info:eu-repo/semantics/openAccess https://creativecommons.org/licenses/by/4.0/ CC-BY ISSN: 0024-4937 Lithos, Vol. 386-387, No 106013 (2021) info:eu-repo/classification/ddc/550 Text info:eu-repo/semantics/article Article scientifique info:eu-repo/semantics/publishedVersion 2021 ftunivgeneve https://doi.org/10.1016/j.lithos.2021.106013 2022-02-08T22:31:09Z Late Triassic – Jurassic igneous rocks of the Antarctic Peninsula and Patagonia provide evidence for the evolution of the margin of southwestern Gondwana. We present new geochronological (LA-ICP-MS zircon U\Pb dates) analyses of 12 intrusive and volcanic rocks, which are complemented by geochemical and zircon isotopic (Hf) as well as whole rock isotopic (Nd, Sr) data. These are combined with similar analyses of 73 other igneous rocks by previous studies, to constrain the magmatic evolution and Late Triassic – Jurassic tectonic setting. The distribution of crystallisation ages reveals four main magmatic pulses that collectively span ~225–145 Ma, all of which have compositions that are consistentwith a continental arc setting. The first episode occurred between ~223–200Ma, and records active margin magmatismwithin the Antarctic Peninsula and northern Patagonia, and reveals the presence of a flat-slab that gave rise to magmatism in eastern Patagonia. After a period of magmatic quiescence (~200–188 Ma), the second episode occurred between ~188 and 178 Ma, with a continuation of arc magmatismabove a flattened slab. The third episode spanned ~173–160Ma, and its geographic distribution suggests the slab was steepening, driving magmatism towards the south and west in Patagonia. Finally, the fourth period occurred between ~157 and ~ 145 Ma, during which time magmas were emplaced along the Antarctic Peninsula and western Patagonia, with no evidence for flat-slab subduction. The analysed rocks include the Chon Aike magmatic province, which has been considered to have been influenced by the break-up of Gondwana, via heating associatedwith the Karoo plume in southern Africa and the activemargin in western Patagonia and the Antarctic Peninsula. Our newdata and revised compilation nowsuggest that the Early -Middle Chon Aike Jurassic silicic magmatic province in Patagonia and the Antarctic Peninsula can be entirely accounted by active margin processes. We also show that the final stage of Jurassic magmatism (~157–145 Ma) was coincident with rifting that formed oceanic lithosphere of the Weddell Sea and back-arc extension of the Rocas Verdes Basin, potentially revealing the presence of a triple junction located between southern Patagonia and the northern Antarctic Peninsula that led to the disassembly of southern Gondwana. Article in Journal/Newspaper Antarc* Antarctic Antarctic Peninsula Weddell Sea Université de Genève: Archive ouverte UNIGE Antarctic Antarctic Peninsula Patagonia Rocas ENVELOPE(-56.948,-56.948,-63.398,-63.398) The Antarctic Weddell Weddell Sea Lithos 386-387 106013 |
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Open Polar |
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Université de Genève: Archive ouverte UNIGE |
op_collection_id |
ftunivgeneve |
language |
English |
topic |
info:eu-repo/classification/ddc/550 |
spellingShingle |
info:eu-repo/classification/ddc/550 Bastias Silva, Miguel Joaquin Spikings, Richard Alan Riley, Teal Ulianov, Alexey Grunow, Anne Chiaradia, Massimo Hervé, Francisco A revised interpretation of the Chon Aike magmatic province: Active margin origin and implications for the opening of the Weddell Sea |
topic_facet |
info:eu-repo/classification/ddc/550 |
description |
Late Triassic – Jurassic igneous rocks of the Antarctic Peninsula and Patagonia provide evidence for the evolution of the margin of southwestern Gondwana. We present new geochronological (LA-ICP-MS zircon U\Pb dates) analyses of 12 intrusive and volcanic rocks, which are complemented by geochemical and zircon isotopic (Hf) as well as whole rock isotopic (Nd, Sr) data. These are combined with similar analyses of 73 other igneous rocks by previous studies, to constrain the magmatic evolution and Late Triassic – Jurassic tectonic setting. The distribution of crystallisation ages reveals four main magmatic pulses that collectively span ~225–145 Ma, all of which have compositions that are consistentwith a continental arc setting. The first episode occurred between ~223–200Ma, and records active margin magmatismwithin the Antarctic Peninsula and northern Patagonia, and reveals the presence of a flat-slab that gave rise to magmatism in eastern Patagonia. After a period of magmatic quiescence (~200–188 Ma), the second episode occurred between ~188 and 178 Ma, with a continuation of arc magmatismabove a flattened slab. The third episode spanned ~173–160Ma, and its geographic distribution suggests the slab was steepening, driving magmatism towards the south and west in Patagonia. Finally, the fourth period occurred between ~157 and ~ 145 Ma, during which time magmas were emplaced along the Antarctic Peninsula and western Patagonia, with no evidence for flat-slab subduction. The analysed rocks include the Chon Aike magmatic province, which has been considered to have been influenced by the break-up of Gondwana, via heating associatedwith the Karoo plume in southern Africa and the activemargin in western Patagonia and the Antarctic Peninsula. Our newdata and revised compilation nowsuggest that the Early -Middle Chon Aike Jurassic silicic magmatic province in Patagonia and the Antarctic Peninsula can be entirely accounted by active margin processes. We also show that the final stage of Jurassic magmatism (~157–145 Ma) was coincident with rifting that formed oceanic lithosphere of the Weddell Sea and back-arc extension of the Rocas Verdes Basin, potentially revealing the presence of a triple junction located between southern Patagonia and the northern Antarctic Peninsula that led to the disassembly of southern Gondwana. |
format |
Article in Journal/Newspaper |
author |
Bastias Silva, Miguel Joaquin Spikings, Richard Alan Riley, Teal Ulianov, Alexey Grunow, Anne Chiaradia, Massimo Hervé, Francisco |
author_facet |
Bastias Silva, Miguel Joaquin Spikings, Richard Alan Riley, Teal Ulianov, Alexey Grunow, Anne Chiaradia, Massimo Hervé, Francisco |
author_sort |
Bastias Silva, Miguel Joaquin |
title |
A revised interpretation of the Chon Aike magmatic province: Active margin origin and implications for the opening of the Weddell Sea |
title_short |
A revised interpretation of the Chon Aike magmatic province: Active margin origin and implications for the opening of the Weddell Sea |
title_full |
A revised interpretation of the Chon Aike magmatic province: Active margin origin and implications for the opening of the Weddell Sea |
title_fullStr |
A revised interpretation of the Chon Aike magmatic province: Active margin origin and implications for the opening of the Weddell Sea |
title_full_unstemmed |
A revised interpretation of the Chon Aike magmatic province: Active margin origin and implications for the opening of the Weddell Sea |
title_sort |
revised interpretation of the chon aike magmatic province: active margin origin and implications for the opening of the weddell sea |
publishDate |
2021 |
url |
https://archive-ouverte.unige.ch/unige:152181 |
long_lat |
ENVELOPE(-56.948,-56.948,-63.398,-63.398) |
geographic |
Antarctic Antarctic Peninsula Patagonia Rocas The Antarctic Weddell Weddell Sea |
geographic_facet |
Antarctic Antarctic Peninsula Patagonia Rocas The Antarctic Weddell Weddell Sea |
genre |
Antarc* Antarctic Antarctic Peninsula Weddell Sea |
genre_facet |
Antarc* Antarctic Antarctic Peninsula Weddell Sea |
op_source |
ISSN: 0024-4937 Lithos, Vol. 386-387, No 106013 (2021) |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.1016/j.lithos.2021.106013 unige:152181 https://archive-ouverte.unige.ch/unige:152181 |
op_rights |
info:eu-repo/semantics/openAccess https://creativecommons.org/licenses/by/4.0/ |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/10.1016/j.lithos.2021.106013 |
container_title |
Lithos |
container_volume |
386-387 |
container_start_page |
106013 |
_version_ |
1766255205722095616 |